This invention relates to an apparatus for handling stands of pipe, as when making up and breaking out long strings of pipe used in a borehole for drilling wells. The apparatus is supported by a travelling block suspended by cables in a drilling rig mast and is adapted to encircle and support a string of drill pipe by engagement with the tool joint of the end of the pipe. Devices of this type are referred to in the petroleum drilling industry as "elevators."
One of the problems with the present day elevators is that of matching the elevator to the particular type of drill pipe being used. In the industry today the use of 31/2 , 4, 41/2 and 5 inch drill pipe is common. In addition, with any given size of drill pipe there are a variety of different shoulder configurations on the tool joints integrally formed at the end of the drill pipe. For these reasons a wide variety of different elevators must be manufactured and carried by supply houses to meet the demands of the drilling industry. An object of this invention is to provide an improved elevator which is capable of being utilized on a variety of sizes of drill pipe, for instance, form 31/2 inch to 5 inch, using the same elevator body with different small and relatively inexpensive commponents.
In Guier U.S. Pat. No. 3,063,509 there is described a useful and effective apparatus and system for handling stands of drill pipe. The system involves the use of an elavator of particular design which has two shoulders and overhanging hooks, which can be engaged respectively by two bails which are supported from the traveling block. On the rotary table there are two horizontal spaced apart parallel rails, one on each side of the drill pipe receiving central opening. These rails are co-linear continuations of a pair of rails supported on the floor of the derrick at the level of the top of the rotary table. The elevator has a base which is adapted to seat on the rails and be guided by the rails so that the elevator can be moved horizontally from a position over the rotary table to a position displaced along the rails from the rotary table, where it can remain while the rotary table is turning, and the pipe is drilling.
By the use of two elevators there is always one elevator on the rails displaced from the rotary table while the second elevator is raising or lowering pipe. When the pipe is lowered into the borehole through the rotary table, it is supported in the elevator. The bails are automatically released from the overhanging hooks and slid along the rails where they are made to engage the overhanging hooks of the second elevator, which can then be lifted to bring a second stand of pipe, for example, to be joined with the pipe supported in the elevator on the rotary table. After the new stand of pipe is made up, the pipe is lifted by the second elevator, and the first elevator is then removed from the pipe and is slid along the rails to the waiting position. The pipe is then lowered and supported in the rotary table by the second elevator, and so on.
The elevators utilized in the dual automatic elevator system of U.S. Pat. No. 3.063,509 includes automatic means for locking the elevator bails to the elevator when the bails are engaged for lifting the elevator. This automatic locking means is not required if the elevator is utilized for the commonly used procedure wherein only single elevators are employed. This invention provides interchangeable bases to the elevator, so that an elevator body may be utilized for the commonly employed single elevator system, or with the use of a different base, the dual elevator system of U.S. Pat. No. 3,063,509.
Another problem with elevators in use today is that they must customarily be manually unlatched to release them from engagement with drill pipe. This is particularly disadvantageous in a dual elevator system. The present disclosure incudes means whereby a remotely controlled pressure signal may be employed to automatically unlatch the elevator as desired.
Another problem encountered with the use of elevators is that they sometimes are not properly inclined at the correct angle when swung into position by an operator to engage and lock around a drill pipe. Side door elevators, including the type illustrated in U.S. Pat. No. 3,063,509, include a finger on the door which, when engaged with a length of drill pipe, causes the door to close. This works efficiently and the pipe is received satisfactorily within the elevator as long as the axis of the opening through the elevator is parallel to the axis of the drill pipe as the elevator is swung into position to engage the drill pipe. Since elevators are normally pivotally swung from bails there presently exists no easy way of controlling the angle of the elevator relative to the bail. This invention provides a means of selectably varying the angle of the axis of opening through the elevator relative to the vertical so that it can be adjusted to be most convenient for use by the operator in engaging drill pipe.